Method of making waterproof igniting compositions



Patented Aug. 30, 1938 UNITED STATES PATENT OFFiCE METHOD OF MAKINGWATERPROOF IGNITING COMPOSITIONS Sweden No Drawing. Original applicationNovember 20,

1933, Serial No. 698,94 plication May 15, 193

2. Divided and this ap- 6. Serial No. 80,022. In

Sweden November 28, 1932 3 Claims.

This application is-a division of Serial No. 693,942, filed November 20,1933.

In countries with a very humid climate the usual safety match has provedinsufliciently resistive to the influence of the moist air, and thereasons for this fact are among other things the following. As the headsof the matches, as a rule, are porous, the moist air can easilypenetrate even into the interior parts of the heads, thereby subjectingthe whole igniting mass to the influence of the humidity. As the greaterpart of the head consists of salts soluble in water, these salts willdisappear partially due to the influence oi the humidity, and-as thebinding l agent is capable of absorbing considerable amounts of water,it will lose its rigidity and be loosened from the match splint, whenthe latter is rubbed against an igniting surface.

Because of the absence of an oxidizing agent which is insoluble in wateras substitution for the chlorate usually employed, experiments withmoisture-proof igniting composition, have only had for their object, asa rule, to flnd an insoluble binding agent. Many proposals with thisobject in view have also been made, but they have always proved tosuiler from drawbacks, which have rendered them less flt for commercialuse.

Thus, for instance, an admixture of linseed oil or latex to thecomposition has been made. These substances, however, render theigniting mass less ignitable so that only up to 6-7 per cent could beused with advantage, whereas considerably larger amounts are required inorder to reliably imbed the chlorate in the binding agent to affordprotection against moisture. It is thus evident that in this way therewill be obtained no essential improvement, but on the contrary animpairment, in as much as the moisture that enters can only be caused todisappear with great diiliculty, whereas igniting compositionscontaining a water soluble binding agent may, as a rule, again be fitfor use after having been dried for a little while.

Furthermore, proposals have also been made to use some easilycombustible substances dlssolved in organic solvents, as nitro-cellulosein amyl acetate and resin in spirits, but in case of the admixture of asuflicient quantity of chlorate to permit ignition of the compositionagainst a striking surface, there will occur a very violent combustionof very short duration, rendering the transfer of the flame to thesplint diflicult.

Another proposal involves the employment of a product of condensation,in which case the igniting composition has been prepared by mixing therequisite chemicals with water, phenol, aldehyde, and a catalyst. Thismethod, however, sufiers from considerable inconveniences due to thefact that the igniting mass, even after drying, still contains largeamounts of water which cannot be removed. The product of condensationproduced is by itself incombustible and cannot, as a result, aid in thedevelopment of power during the combustion, but on the other hand 10large amounts of heat are required to vaporize the water included. Thecombustion will, consequently, take place at a low temperature, and thiscircumstance together with the smothering eifect of the water vaporsresults, as a rule, in a suppression of the flame so that the ignitingmass may only glow. From manufacturing point of view still anotherdrawback arises, namely, that the binding agent under consideration mayonly for a very short while maintain a consistency suitable for thedipping action.

It is an object of this invention to overcome all these drawbacks by anew method of producing a moisture-proof initial igniting body whichconsists in mixing in an organic solvent, to form a pasty mixture, anartificial resin, as a binding agent a chlorate of alkali, andcombustible and filling materials, said artificial resin amounting to atleast 15 per cent by weight and said chlorate of alkali amounting to atleast 50 per cent by weight of the dry ingredients, and forming suchmixture into an igniting body, whereupon the solvent is caused toevaporate.

By the use of such a high amount of chlorate of alkali the sensibilityof the mass to ignition will still be sufiiciently high, even when sucha large amount of binding agent as 20-30 per cent is used, which still,in turn, affords a reliable protection of the imbedded chlorate grainsagainst moisture. As, on the other hand, the binding agent may by itselfburn at a very low speed of combustion, a reduction of the speed ofcombustion of the igniting mass will consequently result, so that thecombustible substance of the match splint (as wood, cardboard, stearinand so on) may have sufilcient time to be ignited.

The artificial resin most suitable as binding agent is an intermediateproduct in the preparation of resite known as resol. A productespecially fit for the purpose may be prepared, for instance, asfollows: 100 parts phenol, 100 parts formaline, and 5 parts ammonia areheated to about 100 C., until a heavy muddiness appears as result of theprecipitated resol, which is al lowed to settle to the bottom and thencan be easily separated. This product is insoluble in water but easilysoluble in alcohol, acetone and other usual solvents. The preparation ofthe igniting mass can either be effected by first dissolving the resolin alcohol and then admixing the other substances to be included in themass, or by grinding the resol together with one or more of thesubstances not developing oxygen, and then moistening the mixture withalcohol and admixing the remaining chemicals. Such an igniting mass'maybe of the following composition:

Potassium chlorate 59 parts Potassium bichromate 1 part Manganesedioxide 3 parts Sulphur 6 parts Powdered glass 6 parts Resol 25parts-i-alcohol 17.5 P rts 100 parts The igniting mass thus producedwill not solidify so rapidly as the well-known product of condensationabove referred to, but can be maintained at a pasty consistency for along while.

The igniting mass of the above stated composition is fit for use aspaste in the heading of matches which may be dried in the usual wayafter the heads have been put on. If it is desired toimpart to the matchheads an especially high degree of hardness this may be effected byhardening at a temperature of 100-150 C. Ac cording to the time andtemperature of the hardening process the resol will then be converted,less or more, into the final product, resite, which is non-burning.Moreover, the hardening process may be accelerated or carried out atlower temperature if a small quantity of, for instance, hexamethylenetetramine is added. Because of the heat required for the hardeningprocess it is advisable, to parafiine the matches after the hardeninginstead of before the dipping, as is amasce otherwise usual, as in othercase the paramne will melt and flow away. Since the hardening processhas the efiect of reducing the speed of combustion of the ignitingcomposition, it is possible, by moderating the degree of hardening, toregulate the speed of combustion within wide limits.

Artificial resins may also be employed for the igniting composition ofigniting rods, and the desired speed of combustion may be obtained byaccordingly regulating the degree of hardening.

What I claim is:-

1. A method of manufacturing a moistureproof initial igniting body whichconsists in mixing in an organic solvent, to form a pasty mixture,resol, a chlorate of alkali, and combustible and filling materials, saidresol amounting to between 15 and 30 per cent and said chlorate ofalkali amounting'to at least per cent by weight of the dry ingredients,forming such mixture into an igniting body, and evaporating the solvent.

2. A method of manufacturing a moistureproof initial igniting body whichconsists in mixing in an organic solvent, to form a pasty mixture, resoland a chlorate of alkali, and combustible and filling materials, saidresol amounting to between 15 and 30 per cent and said chlorate ofalkali amounting to at least 50 per cent by weight of the dryingredients, forming such mixture into an igniting body, evaporating thesolvent, and converting the resol into resite by heat treatment.

3. A method of manufacturing a moistureproof initial igniting body whichconsists in mixing in an organic solvent, to form a pasty mix ture, aresol, a chlorate of alkali, and combustible and filling materials, saidresole amounting to between 15 and 30 per cent and said chlorate ofalkali amounting to at least 50 per cent by weight of the dryingredients, applying such mixture to match splints, evaporating thesolvent, converting the resol into resite by heat treatment, andafterwards paraifining the matches.

LARS ERIK LARSSON.

